Modeling a Comet Airburst

Posted 03.31.09

NOVA

What would happen if a small asteroid moving at 30,000 miles an hour slammed into Earth? In this video, Mark Boslough, a theoretical physicist at Sandia National Laboratories, demonstrates how, even if the asteroid exploded high in the atmosphere, temperatures at the ground beneath would be as hot as the surface of the sun, and wind speeds of the resulting searing gas would be beyond hurricane force. "This is one of the most extreme events, I think, that could ever happen on the surface of the Earth," Boslough says, likening it to a white-hot tornado.

Transcript

Modeling A Comet Airburst

Posted: March 1, 2009

NARRATOR: It's hard to imagine what effects an extraterrestrial explosion would have on the Earth.

But there is one place in Albuquerque, New Mexico that can give you a pretty good picture. Though getting into the visualization room at Sandia Labs, a highly secure defense department laboratory, is no easy task. Sandia Labs is where 90 percent of the components of U.S. nuclear bombs are designed.

MARK BOSLOUGH: The closest thing we have to an asteroid airburst is a nuclear explosion. If you drill down and look at what's happening on a very short time scale, the energy release is very different, but then that effect is very similar.

ANNOUNCER: Observers without goggles must face away from the blast.

MARK BOSLOUGH: The structures burst into flame and then the shockwave would go past. Trees would blow over. That's very similar to what you would get for an asteroid explosion.

NARRATOR: Mark Boslough is a theoretical physicist at Sandia Labs who models cosmic impacts and explosions. He says some extraterrestrial events don't even hit the earth, but can still be devastating.

MARK BOSLOUGH: Here we have an animation of an asteroid on final approach to the earth and what I'm going to show are some simulations of what I think happens when an asteroid like this explodes in the atmosphere.

In our previous way of looking at things, we assumed that the point of the explosion was very much just like a big bomb going off. But now we have these high-performance computers that allow us to retain the momentum. So, in this simulation, I bring in an asteroid—a small asteroid—about 30,000 miles an hour and it explodes three miles above the surface, but it doesn't stay there. It continues to descend at a very high speed.

It's like a moving bomb going off, so in this case, the explosion is still at fairly high altitude. All that energy descends, but as a big, strong, very hot puff of gas. So, at ground zero, temperatures as hot as the surface of the sun, wind speeds beyond hurricane force. I mean this rotation—this vortex--is moving at supersonic speed, so it's like an ultra white-hot tornado. And this one of the most extreme events, I think, that could ever happen on the surface of the Earth.

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